The evidence
Each criterion with what we found, where we found it and when. Anything we could not confirm says so.
NTH criteria
NTH Framework v1.2. Score 21.2 (raw 16.0 of 100), calibrated so the best hotel in this edition (Santa Monica Proper Hotel) reads 90. Evidence retrieved 2026-10-22.
Sleep0.0 / 24
The room as an instrument for deep, uninterrupted, circadian-aligned rest.
Mattress & sleep system
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 5 pts
Unknown
Bedding & textiles
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 4 pts
Unknown
Sleep programme & pillow menu
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 3 pts
Unknown
Blackout
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Circadian & warm evening lighting
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
In-room red light
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Acoustic quiet
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 4 pts
Unknown
EMF & Wi-Fi-off options
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Air0.0 / 12
What you breathe for eight hours a night: filtered, fresh, smoke-free and unperfumed.
In-room purification
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 5 pts
Unknown
Ventilation & building standard
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 3 pts
Unknown
Smoke-free policy
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Fragrance-free & low-allergen rooms
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Water0.0 / 12
Clean water to drink, and to shower and bathe in.
Filtered drinking water
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 5 pts
Unknown
Shower & bath filtration
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 5 pts
Unknown
Gentler pool & hydrotherapy water
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Nourishment0.0 / 10
Food and drink that heal rather than merely please.
Organic & local sourcing
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 4 pts
Unknown
Clean-ingredient standard
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 3 pts
Unknown
Clean minibar & in-room hydration
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Nutrition guidance
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 1 pts
Unknown
Movement5.0 / 10
The means to train, stretch and move, indoors and out.
Gym completeness
Hotel-reported · across the property
Fitness center 7am to 9pm.
Classes & studios
Hotel-reported · across the property
Morning yoga class; private yoga and personal training.
Swimming
Hotel-reported · across the property
Heated swimming pool.
Outdoor activity
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Holistic Wellness7.0 / 19
Healing traditions and the recovery technology that complements them.
Spa facility
Hotel-reported · across the property
Five treatment rooms; steam and rain showers.
Traditional & integrative modalities
Hotel-reported · across the property
Shiatsu, reflexology, Ashiatsu, Samunprai Thai poultice, five-element bodywork.
Mind & breath
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Heat therapy
Hotel-reported · across the property
Steam.
Cold therapy
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Photobiomodulation & PEMF
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Clinical longevity (IV, HBOT, diagnostics)
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 4 pts
Unknown
Materials & Setting4.0 / 13
What touches the skin and surrounds the stay: finishes, products, cleaning, and the landscape beyond the door.
Natural, low-VOC finishes
Hotel-reported · in the best room
Spa built of reclaimed wood, water and stone.
Clean bath & body amenities
Hotel-reported · in the best room
Red Flower shower amenities (spa).
Non-toxic spa & nail products
Hotel-reported · across the property
Plant-based products, organic whenever possible.
Non-toxic housekeeping & plastic-free operations
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Green & blue space
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Walkability & low-impact mobility
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Our review
At a glance
- Fragrance
- 5 not yet reviewed
- Air
- 1 hotel-reported, 1 not met, 3 not yet reviewed
- Cleaning & care
- 4 not yet reviewed
- Sleep & materials
- 1 hotel-reported, 4 not yet reviewed
- Water & pools
- 4 not yet reviewed
- Food
- 2 not yet reviewed
- Light & quiet
- 2 not yet reviewed
- Building
- 3 not yet reviewed
Two reported by the hotel; one not met; the rest not yet reviewed.
2 hotel-reported1 not met22 of 25 not yet reviewed
Counts cover the 25 scored criteria; the other 5 windows are context.
Checked
Read the full profileThe ledger
Fragrance
Added scent is the most common complaint from sensitive guests, and the hardest thing to see on a booking page.
No added fragrance in rooms
Not yet reviewed.
No scent marketing
Not yet reviewed.
Fragrance-free laundry
Not yet reviewed.
Unscented bath products
Not yet reviewed.
So far, the hotel says: The spa’s showers are stocked with Red Flower amenities.
Our note. Whether an unscented option is offered, in the spa or in the rooms, is not stated.
How we know
What we look for. Fragrance-free toiletries in the room by default, or on request.
Why it matters. Fragrance ingredients are among the most frequent causes of allergic contact reactions to cosmetics. An unscented option lets sensitive guests use what is provided instead of packing their own.
Source: EU Scientific Committee on Consumer Safety, Opinion on fragrance allergens in cosmetic products ()
Source 1: Hotel website: Shibui SpaUndated · read 22 Oct 2026
Unscented spa options
Not yet reviewed.
So far, the hotel says: Traditional Japanese shiatsu is given fully clothed and ‘no oil is applied’; many other treatments use essential-oil blends.
Our note. Whether the steam showers are ever scented is not stated, so this falls short of the criterion.
How we know
What we look for. Treatments, saunas and steam rooms available without essential oils or scent infusions.
Why it matters. Essential oils are fragrance: the EU’s scientific committee lists several natural extracts, as well as single fragrance chemicals, among established contact allergens. A shared sauna with a scent infusion is hard to avoid.
Source: EU Scientific Committee on Consumer Safety, Opinion on fragrance allergens in cosmetic products ()
Source 2: Hotel website: Shibui Spa menu (PDF)Undated · read 22 Oct 2026
Know something about fragrance here that we don’t? Tell us
Air
What you breathe for eight hours a night: smoke history, fresh air, filtration and anything burning in the room.
Smoke-free property
Not yet reviewed.
Opening windows
Hotel-reportedonly some rooms or areas
The hotel says: The Courtyard King has ‘French doors with a Juliet balcony that opens onto the hotel’s serene inner courtyard’, and the Studio and Courtyard Suites have French doors with Juliet balconies over the courtyard.
Our note. Other room types are not described with opening windows.
How we know
What we look for. Guest rooms have windows or doors that open to outside air.
Why it matters. The US EPA lists opening windows, when outdoor air allows, as a way to dilute pollutants released indoors. An opening window lets guests air a room themselves when it smells of cleaning products or new furnishings.
Source: US EPA, Improving indoor air quality ()
Source 3: Hotel website: accommodationsUndated · read 22 Oct 2026
Filtered fresh air
Not yet reviewed.
In-room air purifier
Not yet reviewed.
No in-room combustion
Not metin some rooms or areas
The hotel says: The Fireplace Corner Suite has a stone ‘working fireplace’ in its living room.
Our note. The fuel is not stated. Rooms such as the Courtyard King and Superior King are described without a fireplace; ask for one of those if smoke bothers you.
How we know
What we look for. No gas fireplaces, candles or incense in guest rooms.
Why it matters. In homes with gas appliances, the US EPA notes that indoor nitrogen dioxide often exceeds outdoor levels, and that it irritates the eyes, nose, throat and airways. Candles and incense burn in the same small, closed room.
Source: US EPA, Nitrogen dioxide’s impact on indoor air quality ()
Source 4: Hotel website: Fireplace Corner SuiteUndated · read 22 Oct 2026
Know something about air here that we don’t? Tell us
Cleaning & care
How a room is cleaned, treated and prepared, and whether a request for a gentler clean is actually honored.
Low-chemical housekeeping
Not yet reviewed.
No ozone or biocide treatments
Not yet reviewed.
Low-chemical pest control
Not yet reviewed.
Sensitive-guest preparation
Not yet reviewed.
Know something about cleaning & care here that we don’t? Tell us
Sleep & materials
The textiles, mattress and floor you spend the night closest to, and how allergen-aware the room is.
Tested or organic bed linen
Not yet reviewed.
Mattress materials disclosed
Not yet reviewed.
So far, the hotel says: King beds are ‘handcrafted by Savoir’.
Our note. The mattress materials and how flame-retardancy is achieved are not stated.
How we know
What we look for. The hotel says what its mattresses are made of and how flame-retardancy is achieved.
Why it matters. Flame retardants have been added to mattresses and seating foam, and the US National Institute of Environmental Health Sciences lists possible effects including endocrine and thyroid disruption. How much a mattress adds to anyone’s exposure is still debated; disclosure lets guests choose.
Source: US National Institute of Environmental Health Sciences, Flame retardants (undated)
Source 3: Hotel website: accommodationsUndated · read 22 Oct 2026
Hard floors
Hotel-reportedonly some rooms or areas
The hotel says: Rooms are ‘individually designed with custom furnishings, Siberian oak floors, and handwoven rugs’.
Our note. Stated for most room types, not all. Rugs sit on the oak, so ask for them to be lifted if dust is a concern.
How we know
What we look for. Hard, cleanable floors in guest rooms rather than wall-to-wall carpet.
Why it matters. Dust mites live in carpet, and US health guidance for allergic sleepers is to replace wall-to-wall carpet in bedrooms with bare floors, which can be cleaned completely between guests.
Source: US National Institute of Environmental Health Sciences, Dust mites and cockroaches (undated)
Source 3: Hotel website: accommodationsUndated · read 22 Oct 2026
Allergy-friendly rooms
Not yet reviewed.
Pet-free rooms
Not yet reviewed.
So far, the hotel says: Dogs and cats are welcome with ‘no additional fee or size limitation’, in rooms and in the Drawing Room, Courtyard and lobby on a leash.
Our note. Whether any rooms are kept pet-free is not stated.
How we know
What we look for. Rooms or floors where animals are never allowed, cleaned to a separate routine.
Why it matters. Pet allergen can stay on carpets and furniture for months and travels on clothing. For allergic guests a room animals never enter matters more than any amenity.
Source: US National Institute of Environmental Health Sciences, Pet allergens (undated)
Source 5: Hotel website: pet-friendly staysUndated · read 22 Oct 2026
Know something about sleep & materials here that we don’t? Tell us
Water & pools
Drinking water, shower water and pool air.
Filtered or tested drinking water
Not yet reviewed.
Water safety plan
Not yet reviewed.
Shower filters
Not yet reviewed.
Shown for information; not scored.
Outdoor or low-chloramine pools
Not yet reviewed.
Shown for information; not scored.
Know something about water & pools here that we don’t? Tell us
Food
Allergen care first; where the produce comes from second.
Allergen-aware kitchen
Not yet reviewed.
Garden or organic produce
Not yet reviewed.
Shown for information; not scored.
Know something about food here that we don’t? Tell us
Light & quiet
Darkness and silence at night, and radio-quiet options for guests who want them.
Darkness and quiet
Not yet reviewed.
Radio-quiet options
Not yet reviewed.
Shown for information; not scored.
Know something about light & quiet here that we don’t? Tell us
Building
The materials a hotel was built and renovated with, how it handles damp, and what third parties have certified.
Low-emitting materials
Not yet reviewed.
So far, the hotel says: Shibui’s pool sits under the roof of a 250-year-old farmhouse ‘reconstructed in the spa by Japanese craftsmen’.
Our note. An old timber roof reused in the spa, but paints, adhesives, finishes and flooring are not described, so this falls short of the criterion.
How we know
What we look for. Low-VOC paints, adhesives, finishes and flooring specified in construction or renovation.
Why it matters. Paints, varnishes and adhesives release volatile organic compounds, formaldehyde among them, most heavily when new. Low-emitting products reduce that load.
Source: US EPA, Volatile organic compounds’ impact on indoor air quality ()
Source 2: Hotel website: Shibui Spa menu (PDF)Undated · read 22 Oct 2026
Leak and mold response
Not yet reviewed.
Building certification
Not yet reviewed.
Shown for information; not scored.
Know something about building here that we don’t? Tell us
Notes & sources
- Hotel website: Shibui Spa, Undated · read 22 Oct 2026
- Hotel website: Shibui Spa menu (PDF), Undated · read 22 Oct 2026
- Hotel website: accommodations, Undated · read 22 Oct 2026
- Hotel website: Fireplace Corner Suite, Undated · read 22 Oct 2026
- Hotel website: pet-friendly stays, Undated · read 22 Oct 2026
- Hotel website: Courtyard King, Undated · read 22 Oct 2026
- Hotel website: Drawing Room & Courtyard, Undated · read 22 Oct 2026
Room count: Per the hotel’s website. Hotel website (opens the hotel’s website)
Photographs: The Greenwich Hotel; The Greenwich Hotel; The Greenwich Hotel; The Greenwich Hotel; The Greenwich Hotel; The Greenwich Hotel; The Greenwich Hotel
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